Conductor



May 1932 J. J. GILBERT 1,860,500

CONDUCTOR Filed March 1, 1929 //v VfNTOR J J [3/4 amr Patented May 31, 1932 UNITED; STATES JOHN acrmmnr, or DoUGL srromivEw roan, Assmnon '10 BELL TELEPHONE nano- RATORIES,-INCOR10RATED, or NEW YORK, .N. an, A oonroa'arrou or NEWYORK ooNnUoroR Application filed March 1 V In a submarine cable conductor of the ordinary type either solid, or the stranded type consistingof a central core with surrounds in theform of flat spiraled copper strips, the

skin eifect results in the efiectiv'e resistance 5 being increased as the frequency 1ncreases. This occurs because the current tends to concentrate in the outer portion of the conductor.

current will be forced from the surrounds into the central strand or strands. In this manner the overall resistance is reduced and the inductive react-ance increased.

. Relatively light'loading is required and the outer strands may be loaded by electrolytic depositionof magnetic material upon them. Alternatively, the magnetic material may be applied 'by sputtering or by the Schoops pistol.

Where there are several layers of sur-.

rounds each layer may be loaded and theloadteract the increasingskin effect.

Alternatively, the desired inductive reactance may be had by serving the unloaded surrounds with a given number of turns per unit length of conductor. In this case it might be desirable to subdivide the central conducting core in order to reduce the losses due to eddy currents set up in this core by the solenoidal field of the surroundsf Fig. 1 is a cross section of a cable core embodying the featuresof the invention; and

Fig. 2 is a side view of the same cable core satingin part, atleast, for the skin effect.

with the various layers cut away at difie rent ponents thereofi v The details of a representative structure'im volving the invention may be understood from the following description taken in con- 5 nection with the accompanying drawings ing increased towards the outer layer to count points in order to illustratethe several-com- 192a. Serial No. 343,601

which are purely diagrammatic and not intended to' represent relative dimensions of a practical structure.

7 In the drawings the central core 1 is surroundedby the. usual flat strands or surrounds 2. The strands 2 are individually loaded byelectro-deposition upon them or by other suitable'application thereto of magnetic materials 'su chas nickel-iron alloys of high permeability, nic-kel-iron-cobalt alloys or other similar magn'etic'materials, illustrated at' 3. Surrounding the outer strands is the usual magnetic loading material 4. For telephone cables of considerable length theloading material 4 may consist, for example, of a composition of 45% nickel, 25% cobalt, 23% iron, and 7% molybdenum,heat treated to develop high constancy of permeability in a range of low magnetizing forces as is well known, the molybdenum content in such a composition serves to give it a high resistivity of the order of microh'm-cms. In a prac tical structure the entireconductor and loading material will be surrounded by a viscous semi-liquid pressure equalizing substance 5 c of a kind'well known in the art, i. e. bitumen or Ghattertons compound. The conductor thus prepared is surrounded with gutta percha or similar insulating material 6 to form a core. I

Fora deep sea submarine cable conductor of the usual dimensions it will be appropriate to cover-thesurrounds with high permeability 'material to a thickness of about 0.001 inch (0.025 m. 111.). The'hysteresis and eddy current'loss'es in this thin layer of material will be very small.

A conductor having the outer strands loadedin the manner thus described is advantageous in that the impedance of the outer strands is increased, which tends to force more of the current into the central core or the inner strands, thereby compen- Loadinglthe surrounds makes the phase angle of the currents in the inside and outside parts of the conductor more nearly equal, 7 i

or. entirely equal depending upon the fre-. quency and degree of loading. In an 'ordinaryconductorthe skin efiect has the apparmy name, this 26th dag cut result of making the ratio of reactance to resistance lower in the outside part of the conductor than in the inside and this ratio is increased by individually loading the surrounds.

What is claimed is: y

A loaded conductor fo ubm r ne t ephone communication comprising a central portion surrounded by closely fitting surrounding strands, each strand having its induct-ance increased by a thin layer of hi h permeability magnetic material substantia completely covering the external surface of the strand.

2. A submarine cable conductor composed f e e a rands some o whi h lie nearer the exterior o the onductor than others, characterized in this that the extreme outer laye s o t e i idu l e terior str nds ha magnetic material substantially completely surrounding them,

A s bmari cable c nduct h vinga plurality of strands part of which are indii vidu lly subs lly complete y covered up n hei tern l u faces by a thin layer of magn ic mate ial omposed Principally of nickel and iron heat treated in a manner to make it of high permeability. I

4- A c mposite lec r a onducto ha ing a. p ality of strand so o which lie externally of the others and have 83 their uter layer a ay o magne i material, of t e de of 0001. inch i thickness- 5, A composi le t i a tr nded con ine tor in whi h e ta n trands a e ndivid ally substantially completely surrounded by magetie m te al. and the en ire conduc r a a whole is surround d with he magn ti ma terial. i V

A subma in cable ha inga conductor in a r an e wi h claim charac er zed in this, that he b e is in a ed wi h a to gh solid insulat ng material f he. charac er of gu t p r a a d that he strands of. he con uctor and the other magnetic material are completely surrounded by a viscous or semiliquid pressure equalizing substance,

7. A composite electrical conductor for high frequ y ar ne cab communiea tion having a conductor composed of a central portion and closely fitting surrounding strands in which the inductance of the closely fitting surrounding strands as compared to the inductance of the central portion, is creased by magnetic loading material, characterized in this that the loading material is high permeability, high resistivity material in thickness of the order of 0.001 inch,

In Witness whereof, I hereunto subscribe of eb uary, 1929- HN J GILBERT. 

